Attenuation-to-crosstalk ratio

Attenuation-to-crosstalk ratio (ACR) is a parameter that is measured when testing a communication link, which represents the overall performance of the cable.[1] ACR is a mathematical formula that calculates the ratio of attenuation to near-end crosstalk for each combination of cable pairs.[2] ACR is expressed as a figure in decibels (dB), between the signal attenuation produced by a wire or cable transmission medium and the near-end crosstalk (NEXT).[3] In order for a signal to be received with an acceptable bit error rate, the attenuation and the crosstalk must both be minimized.[3] Crosstalk can be reduced by ensuring that twisted-pair wiring is tightly twisted and is not crushed, and by ensuring that connectors between wire and cable media are properly rated and installed.[3]

Positive ACR calculations mean that transmitted signal strength is stronger than that of near-end crosstalk.[4] ACR can be used to define a signal bandwidth (e.g. 250 MHz for category 6 cable) where signal to noise ratios are sufficient to support certain applications.[4] The maximum frequency for which positive ACR is assured provides a benchmark to assess the usable bandwidth of twisted-pair cabling systems.[4] EIA/TIA specifies specific values for ACR in order to meet the various categories of cable.[5]

See also

References

  1. ↑ , Learning Path: Testing network cable.
  2. ↑ , Testing Copper Cabling the Right Way.
  3. 1 2 3 , attenuation-to-crosstalk ratio (ACR) or headroom.
  4. 1 2 3 "Archived copy". Archived from the original on 2011-04-27. Retrieved 2011-05-06., De-Mystifying Cabling Specifications - Important Definitions.
  5. ↑ CAT 6 Testing Requirements Archived May 8, 2011, at the Wayback Machine.


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